State-of-the-art vertical-cavity surface-emitting lasers (VCSELs) as described, for example, in U.S. Pat. No. 5,596,595 need a current aperture for electrical and optical confinement. This is usually realized by lateral oxidation of a high aluminum containing layer. The lateral oxidation may cause reliability issues.
US 2012/0128020 A1 discloses to integrate a phototransistor layer structure into the layer stack of a Vertical Cavity Surface Emitting Laser (VCSEL).